1. Field of the Invention
The present invention relates generally to an optical waveguide device having an optical waveguide chip, and more particularly to a connection structure between an optical waveguide chip and an optical fiber in such an optical waveguide device.
2. Description of the Related Art
In recent years, an optical waveguide chip having an optical waveguide structure has been widely developed to be put to practical use. In incorporating the optical waveguide chip into a system, optical connection between an optical fiber as a transmission line and the optical waveguide chip is indispensable, and a structural improvement of the optical connection has now been desired.
Conventionally, an optical waveguide device constructed by connecting an optical waveguide chip and an optical fiber by an adhesive is known. The optical waveguide chip has an optical waveguide structure. The optical waveguide chip and the optical fiber are fixed to each other so that a connection end corresponding to an end surface of the optical waveguide structure and an excitation end of the optical fiber are opposed to each other in close contact.
Also known is another optical waveguide device including an optical waveguide chip, a first optical fiber for connection, and a second optical fiber as a transmission line. The first optical fiber has first and second excitation ends. The optical waveguide chip and the first optical fiber are accommodated in a housing, and a connection end of the optical waveguide chip and the first excitation end of the first optical fiber are connected together by an adhesive. The second excitation end of the first optical fiber accommodated in the housing is detachably connected to an excitation end of the second optical fiber by an optical connector structure.
In these conventional optical waveguide devices, the connection end of the optical waveguide chip and the excitation end of the optical fiber (the first excitation end of the first optical fiber) must be connected together by the adhesive. Accordingly, a complicated operation for positioning or the like is required, so that optical connection between the optical waveguide chip and the optical fiber (the first optical fiber) is not simple.
Particularly in the latter conventional optical waveguide device, two connection points are present between the optical waveguide chip and the second optical fiber as the transmission line, causing an increase in connection loss.